My transmission shifts really good but when im in overdrive driving a steady 60 its slips just a little and slips back, continues till its hot and quits no more slipping

Question edited for clarity.

All your issues can be solved by an auto electrician or a transmission specialist with a $5k pro grade scan tool computer. TCM or solenoids. It is an electronic issue.

This is possible the overdrive switch is deactivated and you don't know it because the bulb is burned out and your missing that shift point and rpm's high ,but is it slipping coming out of gear with high rpm's there's a difference the code 760 is a solenoid c malfunction that's coming up and could be the first description or the second one if it's just not shifting with no slipping and coming out of gear it's the solenoid switch that has failed and you can still drive it till you get the cash to fix it but NO HIGHWAY JUST LOCAL EASY DRIVING WILL NOT KILL YOUR CAR THE OVERTIME DOESN'T HAPPEN TILL AFTER 35MPH AND IT WOULD BE THE EQUIVALENT OF DRIVING A STICK IN 3RD GEAR OF A 4 SPEED MANUAL OR 4TH IN A 5 SPEED JUST LIGHT DRIVING BACK N FORTH TO WORK OR WHATEVER GO TO ROCKAUTO.COM AND LOOK UP YOUR VEHICLE AND THEN THE PART IN AUTOMATIC TRANSMISSION SECTION THEY ARE THE CHEAPEST FOR THIS AND ALL PARTS ACROSS THE COUNTRY IN THE U.S.A. AND WILL SHIP WORLD WIDE GOOD LUCK STEPHEN

The trans is getting to hot in overdrive this is a protective feature

Shoot the transmission or better yet get a wire and command the overdrive itself to come on. But before you can do this look at the transmission fluid is it burnt or very very dark?And when you check transmission fluid level(car running) is it foaming or you see little bubbles.If you do shoot the transmission. Okay now check throttle cable or TV the one on the throttle body youll have 2 of them with is at wide open throttle take hold of the transmission downshift part does it have 1/4 freeplay it should cause that can affect the downshift.which in turns affects the overdrive. Now lets get to the dirty part in order for this transmission to have over drive. 2 solenoids signal must be in the off postion when the vehicle is in fourth gear . Your not slipping right? Now there is a sensor called O/d direct speed sensor(NC2) it detects rotaion speed of the clutch drum. all this does is detect shift timing by comparing NC@ sensor signal to the VSS vehicle speed sensor. this is the one on top of the transmission its called an input sensor or turbine. Now is the overdrive working yes it is does it feel like it works nope.when you turn on the overdrive and the O/D light is on its only transmission shift quality you only have 4 gears your transmission is a A541E 4 -SPD. Its working fine stop thowing part into it and dont shoot it.

no you have a failed transmission on your hands, it is slipping.

on automatics the overdrive is actualy not in the trans at all
it's a small cluch in the torque converter and is not repairable, the only fix is to replace the torque converter, but then you say it races free as if not in drive?
That's a failure of the forward clutch

I'm afraid you need the trans overhaued, I recomend the dealership and NEVER places like Mr Transmission type, they'll overhaul it wihout any testing and cannot diagnose, just overhaul and overhaul ultil eother you're broke, or give up

In a 250 you most likely have either a C-6 (Aluminum case) or a FMX (Iron case) both are good transmissions and again the overdrive is the torque converter, be sure they replace it too

Good luck

sounds like you need a new overdrive

I had an 89 Suburban that started doing the same thing. Change the fluid/filter and add a quart of Lucas Transmission Fix. See how that does. Ultimately, you are going to have to rebuild or replace the transmission as the problem will only get worse in the end. Mine finally went down completely and cost me about $2700 to rebuild.

well the low cost way to go first would be to try and change the trans fluids. If the problems still remains the it may be an internal problem

you may have damaged the overdrive gear, a local transmission shop would be your best bet. for good troubleshoting and estimate.